Transmission



B. L. FROST TRANSMISSION Sept. 20, 1966 7 Sheets-Sheet 1 Filed Dec. 50,1963 INVENTOR. Lfiw flaw" BY 2 B. L. FROST TRANSMISSION Sept. 20, 1966 7Sheets-Sheet 2 Filed Dec. 50, 1963 5 wLINEZlgTORfi (277' 705 1 BY Sept.20, 1966 B. L. FROST 3,273,415

TRANSMISSION Filed Dec. 50, 1963 7 Sheets-Shae; 4

INVENTOR .Ba'zzylfiaai, BY M W Sept. 20, 1966 B. L. FROST 3,273,415

TRANSMISSION F'iled Dec. 30, 1963 v 7 Sheets-Sheet 5 I NVENTOR.

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Sept. 20, 1966 FROST 3,273,415

TRANSMISSION Filed Dec. 30, 1963 7 Sheets-Sheet 6 m1 ju INVENTOR.

B. L. FROST TRANSMI SS ION Sept. 20, 1966 7 Sheets-Sheet 7 Filed Dec.30, 1963 THE United States Patent O 3,273,415 TRANSMISSION Barry L.Frost, Jackson, Mich assignor to Clark Equipment Company, a corporationof Michigan Filed Dec. 30, I963, Ser. No. 334,204 7 Claims. (Cl. 74-360)My present invention relates generally to power transmission mechanismsfor heavy duty automotive vehicles such as road graders and the like,and more particularly to improvements in a multi-ratio change speedpower transmission mechanism of the type disclosed in the copendingapplication of Ronald H. Bolster, Serial No. 79,365, filed December 29,1960, now Patent No. 3,126,752, issued March 31, 1964.

One embodiment of power transmission mechanism disclosed in theaforesaid co-pending application comprises a rotatable input shafthaving a first clutch gear rotatable thereon and a forward-drive clutchfor selectively connecting the first clutch gear to the input shaft, arotatable reverse shaft having a second clutch gear rotatable thereonand a reverse-drive clutch for selectively connecting the second clutchgear to the reverse shaft, constant mesh gear means driving the reverseshaft from the input shaft, a rotatable idler shaft having an idler gearin constant mesh with the first and second clutch gears, and ratio gearmeans selectively driven from the idler gear and idler shaft. Engagementof the forwarddrive clutch effects drive of the ratio gear means in aforward direction, while engagement of the reverse-drive clutch effectsdrive of the ratio gear means in a reverse direction. The ratio gearmeans, in turn, comprises a plurality of rotatable shafts including anoutput shaft, and a plurality of constantly meshing gears including fouradditional clutch gears rotatable on certain of the shafts with ratioclutches associated therewith. The ratio clutches may be selectivelyengaged for clutching one of the four additional clutch gears to theadjacent shaft whereby any one of four drive ratios may be providedbetween the idler gear or idler shaft and the output shaft. Thistransmission thus has four drive ratios in either a forward or reversedirection of rotation.

It is an object of my present invention to provide a power transmissionmechanism of the general character described, wherein the number ofdrive ratios is in creased, without any increase in the number ofrotatable shafts or in the overall size of the transmission housing, andwithout rearrangement of the location of the axes of the rotatableshafts.

In accomplishing this object, I hav modified the constant mesh gearmeans driving the reverse shaft from the input shaft to include a clutchgear on the input shaft and a second forward-drive clutch associatedtherewith. This clutch-gear means comprises :a clutch hub memberrotatably mounted on the input shaft and a plurality of friction diskmembers carried by the hub member for rotation therewith; also a clutchdrum member having a generally radial flange portion secured to theinput shaft and a generally axial cylindrical portion overlying a partof the hub member and carrying a plurality of friction disk membersinterleaved with the friction disk members of the hub member. Fluidpressure operated means is provided for compressing together the diskmembers of the hub and drum members for selectively clutching the hubmember to the input shaft. A first gear portion, which is provided onthe cylindrical portion of the drum member, has meshing engagement witha gear secured to the reverse shaft; and a second gear portion, which isprovided on the hub member axially outwardly of the cylindrical portionof the drum member, has meshing engagement with a gear secured to theidler shaft.

By engaging the first forward-drive clutch and one of the ratioclutches, the output shaft is driven in one of a first set of fourratios in a forward direction. When the second forward-drive clutch andone of the ratio clutches are engaged, the output shaft is driven in oneof a second set of four ratios in a forward direction. Finally, when thereverse-drive clutch and one of the ratio clutches are engaged, theoutput shaft is driven in one of a set of four ratios in a reversedirection. Accordingly, the transmission has eight drive ratios in aforward direction and four drive ratios in a reverse direction.

Because the clutch gear portion, which has meshing engagement with thegear secured to the reverse shaft, is part of the cylindrical portion ofthe drum member of the second forward-drive clutch, the axial extent ofthe clutch-gear assembly is maintained at a minimum, thereby permittingthe same to be incorporated in a transmission of the type disclosed inthe aforesaid co-pending application, without modifying the size of thetransmission housing. Moreover, the clutch-gear assembly may be usedwithout rearranging the location of the rotatable shafts or altering thearrangement of the ratio gear means driving the output shaft.

Now in order to acquaint those skilled in the art with the manner ofconstructing and using transmissions in accordance with the principlesof my present invention, I shall describe in connection with theaccompanying drawings a preferred embodiment of my invention.

In the drawings:

FIGURE 1 is a perspective view of the exterior of a transmissionincorporating the principles of my present invention;

FIGURE 2 is a perspective view of the transmission of FIGURE 1, takenfrom approximately the same point as FIGURE 1, but with the housing andcover members removed to show the shafts, gears and clutches;

FIGURE 3 is a front elevational view of the transmission of FIGURE 1;

FIGURE 4 is a sectional view, taken substantially along the line 44 ofFIGURE 3, looking in the direction indicated by the arrows;

FIGURE 5 is a vertical sectional view, on an enlarged scale, of one ofthe clutches of FIGURE 4;

FIGURE 6 is a rear elevational view of the transmission of FIGURE 1 withportions of the housing and cover rnember being broken away to showcertain parts which are not visible in other views; and

FIGURE 7 is a two-part diagrammatic representation of the transmissionof FIGURES 1 through 6 showing on the left a developed schematic diagramin which the gears, shafts and clutches are shown with the shaft centersin one plane, and on the right a diagram of the actual positions, asviewed from the rear end, of the centers of the shafts.

Referring now to FIGURES 1 through 4, there is indicated generally bythe reference numeral 10 a transmission incorporating the principles ofmy present invention. The transmission 10 comprises a housing 12 havingfront and rear vertically disposed walls 14 and 16, upper and lowerwalls 18 and 20, and side walls 22 and 24.

Located near the top of the front and rear housing walls 14 and 16 arean input shaft 26 and a laterally spaced reverse shaft 28. The inputshaft 26 is journaled in a pair of bearing assemblies 29 and 29a mountedrespectively in the front and rear housing walls 14 and 16, and thereverse shaft 28, on which is secured intermediate of the front and rearhousing walls 14 and 16 a gear 30, is journaled in a pair of bearingassemblies 31 and 32 mounted respectively in the front and rear housingwalls 14 and 16.

Secured to the input shaft 26 outwardly of the forward housing wall 14is a portion 33 of a coupling device adapted to be connected to thecoupling portion of the drive shaft of prime mover means (not shown).Also mounted on the input shaft 26 intermediate of the front and rearhousing walls 14 and I6 is a clutch assembly indicated generally by thereference numeral 34. As best shown in FIGURE 4, the clutch assembly 34comprises a hub member 35 journaled for rotation on a pair of bearingassemblies 36 mounted on the input shaft 26. The hub member 35 is formedwith a forward clutch gear portion 37 and a rearward axial exteriorlysplined annular portion 38 on which are carried a plurality of frictiondisk mem bers 39. Associated with the hub member 35 is a clutch drummember 40 having a generally radial flange portion 41 secured to theinput shaft for rotation therewith and a generally axial internallysplined cylindrical portion 41a overlying the axial portion 38 of thehub member 35. The cylindrical portion 41a is formed with an externalgear portion 42 in constant mesh with the reverse gear 30, and carriesinternally a plurality of friction disk members 43 interleaved with thefriction disk members 39. i The clutch structure 34 includes a backingplate or ring 44 which is secured at the forward end of the drum 40 asby a snap ring 44a. An annular piston member 45 is provided forcompressing together the disk members 39 and 43 whereby to engage theclutch 34. The piston 45 is mounted for axial movement in a chamber 46which is formed inside the drum 40 adjacent the drum flange 41. Thepiston 45 is moved to the left for clutching action by fluid underpressure which is admitted through a radial passageway 47 in the drumflange 41. Fluid under pressure is directed to the passageway 47 throughan annular groove 48, a radial passageway 49, a forwardly extendingaxial passageway 50, and a radial passageway 51, all formed in the inputshaft 26. The outer end of the passageway 51, in turn, receives fluidunder pressure from a radial passageway 52 and an annular groove 53formed in a sleeve member 54 secured to the input shaft 26 outwardly ofthe forward housing wall 14. Surrounding the sleeve member 54 is a hubmember 55 secured to the housing wall 14 and having a radial passageway56 therein through which fluid under pressure is admitted to the groove53. Engagement of the clutch 34 causes the gear 37 to rotate conjointlywith the drum member 40 and shaft 26. ,When it is desired to disengagethe clutch 34 the source of pressurized fluid is disconnected and fluidis released from the chamber 46 by means of a check valve 46a in thedrum flange 41. Return of the piston 45 to the position shown iseffected by means of a plurality of springs (not shown) extendingbetween the piston 45 and the backing plate 44. Such return springs areof the same construction and arrangement as the springs 15% to bedescribed hereinafter in connection with the clutch assembly disclosedin FIGURE 5. The clutch disks 39 and 43 are cooled by fluid suppliedunder pressure through a radial passageway 57 in the hub member 55,annular groove 58a and radial passageway 58b in the sleeve member 54,and longitudinal slots 59 in the input shaft 26 that communicateinteriorly of the clutch assembly 34. The gear portion 42 is formed onthe cylindrical portion 41a of the drum member 46 so as to minimize theaxial extent of the clutch-gear assembly whereby to permit the same tobe incorporated in a transmission having front and rear housing Walls 14and 16 of a predetermined separation, without alteration thereof.

Located outwardly of the rear housing wall 16 are a clutch 60, which maybe selectively actuated to connect a gear 62 for rotation with the inputshaft 26, and a clutch 64, which may be selectively actuated to connecta gear 66 for rotation with the reverse shaft 28. The detailedconstruction of clutches 6t) and 64 is shown in FIGURE and will bedescribed hereinafter. Both gears 62 and 64 are in constant mesh with agear 68 which is secured outwardly of the rear housing wall 16 to oneend of an idler shaft 70. The shaft 70 is located at a level below theinput and reverse shafts 26 and 28 and is journaled in a pair of bearingassemblies 71 and 71a mounted respectively in the front and rear housingwalls 14 and 16. Secured to the opposite end of the idler shaft '76outwardly of the front housing wall 14 is a gear 72, and secured to theidler shaft 7 0 intermediate of the front and rear housing walls 14 and16 is a gear 73 that is in constant mesh with the gear 37 on the inputshaft 26.

The transmission 10 further comprises a pair of intermediate shafts 74and 76 located at a level below the idler shaft '70. The shafts 74 and76 are each journaled in a pair of bearing assemblies mountedrespectively in the front and rear housing walls 14 and 16, the bearingassemblies for the shaft 74 being identified by the reference numeralsand 75a. Outwardly of the front and rear housing walls 14 and 1.6respectively, the ends of the shaft 74 have associated therewith ratioclutches 78 and 86, and the ends of the shaft 76 have associatedtherewith ratio clutches 82 and S4 (visible in FIGURE 6).

The gear 63 on the idler shaft 70 is in constant mesh with a gear 86,which may be selectively connected by the clutch to the intermediateshaft 74, and also with a gear 88, which may be selectively connected bythe clutch 34 (see FIGURE 6) to the intermediate shaft 76. Similarly,the gear 72 on the idler shaft 79 is in constant mesh with a gear 90,which may be selectively connected by the clutch 78 to the intermediateshaft 74 and also with a gear 92 which may be selectively connected bythe clutch 82 to the intermediate shaft 76.

Mounted on the intermediate shaft 74 for rotation therewith intermediateof the front and rear housing walls 14 and 16 is a gear 94. The gear 94is in constant mesh with a gear 96 which is secured to an output shaft98 located at a level below the intermediate shafts 74 and 76. A gear100 is mounted on the intermediate shaft '76 intermediate of the frontand rear housing walls 14 and 16 and is in constant mesh with a gear 102which likewise is mounted on the output shaft 98. The output shaft 98 isjournalled in the front and rear housing walls 14 and 16 by means ofbearing assemblies 104 and 106.

Mounted on the end of the output shaft 98 adjacent the rear housing wall16 is a portion 102% of a coupling device providing for coupling of theoutput shaft to a propeller shaft (not shown) for operating the rearwheels of a vehicle or other device to be operated by the trans mission.The end of the output shaft 98 adjacent the front housing wall 14 isrecessed and journaled therein is the reduced rearward end portion of anauxiliary optional output shaft 169. Secured to the forward end of theoptional output shaft 109 is a portion 110 of a coupling device whichmay be connected to a corresponding coupling portion (not shown) on theend of a propeller shaft leading to the front wheels of a vehicle orother instrumentality to be driven by the optional output shaft 109.

The clutch structure by which the shaft 169 may be driven from theoutput shaft 98 at the operators option includes a collar member 111rotatable with the shaft 98 and axially shiftable therealong. The collarmember 111 is provided with axially projecting teeth 111a that arearranged to engage the axially projecting teeth 112a on a collar member112 secured to the shaft 199. The collar 111 is slidable axially to theleft by suitable mechanical or power operating mechanism (not shown),and is returned to the right by a return spring 113 when it is desiredto disconnect the shaft 109 from the shaft 98. With this transmissioninstalled in a vehicle, the shaft 109 is connected with the shaft 98when it is desired to provide the vehicle with four-wheel drive;however, when only two-wheel drive is desired, the shaft 169 isdisconnected and the sole drive is provided by the shaft 98 through thecoupling portion 108 at the rearward end thereof.

The details of construction of the clutch 66 are illustrated in FIGURE5. Since the clutches 64, 89 and 84 are identical with the clutch 60,while the clutches 73 and 82 are the same as clutch 611 except as tosize, an explanation of clutch 61) will suffice for all of theseclutches.

In FIGURE 5 there is indicated by the reference numeral 114 a fixedannular sleeve or quill member which is connected by means of a flangeportion 115 thereon to the rear surface of the rear housing wall 16 in asuitable manner such as by a plurality of machine screws 116. As shown,gear 62 is formed integrally on an axial projection 117 extending fromthe radial flange portion 118 of a clutch drum 119. The combined gearand clutch drum structure is rotatably mounted on the tubular portion ofmember 114 by means of a roller bearing assembly 120 and a ball bearingassembly 121. The drum 119 carries a plurality of annular friction disks122 which are splined to the clutch drum interiorly thereof for rotationtherewith. Interleaved between the friction disks 122 are alternateannular disks 124 which are splined to the exterior of an annular hubmember 126 having a radial flange portion 127 secured to the input shaft26 for rotation therewith.

The clutch structure includes a backing plate or ring 12?: which issecured at the outer end of the drum 119 in a suitable manner such as bya snap ring 131). The clutch 60 is engaged by compressing the stack ofdisks 122 and 124, and this is accomplished by an annular piston member132. The piston 132 is mounted for axial movement in a chamber 134 whichis formed inside the drum 119 adjacent the drum flange 118.

The piston 132 is moved to the right by fluid under pressure which isadmitted through a slanted passageway 135 in the member 114 to alongitudinal passageway 136 from which it passes through suitablesealing means to a passageway 138 in the drum member and then intochamber 134 behind or to the left of piston 132 at location 140. Initialmovement on the piston 132 is rapid upon the admission of fluid underpressure because only a small portion of the annular cross sectional endarea of the piston 132 is effective initially. The radial width of thisinitial eflective area is indcated in FIGURE 5 by the numeral 142 andbracket associated therewith. After piston 132 has moved a distance d tothe right and the shoulder portion 144 on the piston passes the shoulder146 on the adjacent drum member, the full annular end area of the piston132 is exposed to pressurized fluid. This, of course, provides muchgreater pressure on the piston. The effect of the structure andoperation just described is that the piston 132 moves rapidly in theinitial stages but with a relatively small force and slowly in theterminal stages with a relatively large force. When it nears the end ofits stroke to the right to provide clutch engagement, the increasedforce on the piston insures complete clutch engagement and lack ofslippage during operation. When it is desired to disengage the clutch611 the source of pressurized fluid is disconnected and fluid isreleased from the chamber 134 by means of a check valve 148. The piston132 is then returned to the position shown by a plurality of springs1511 extending between the piston and the backing ring 128, one of whichis visible near the bottom of FIGURE 5. As indicated in the draw ing,portions of the multiple disks 122 are omitted or cut off at intervalsaround the periphery of these disks, to accommodate the return springs150 which are disposed within the corresponding spline grooves in thedrum 119. For more information concerning the valve 148, reference maybe had to Patent No. 2,954,040 wherein this valve is disclosed in detailand claimed.

For cooling the clutch 60 during the time when it is not engaged andthere is relative motion between the alternate fraction disks, apassageway 151 is provided in the member 114 through which cooling fluidis supplied under pressure to the annular space 152 between the shaft 26and the sleeve member 114. From the space 152, the fluid flows along thepath indicated by the line 154 through a series of openings 156 in thehub member 126, then 6 over the surfaces of the disks 122 and 124 andout through a series of openings 158 in the drum member 119; after whichsuch fluid drains by gravity to the bottom of the housing 12.

As shown in FIGURE 4, the transmission 10 may also be provided with apower take-off indicated generally by the reference numeral 159. Thepower take-off mechanism 159 comprises a shaft 161) which is arranged tobe selectively connected to the shaft 70 in order to drivesimultaneously an auxiliary device on a vehicle or other device inaddition to the mechanism driven by the main output shaft 98. The shaft1611 is jour'naled at one end in a bearing assembly 161 mounted withinthe adjacent end of the shaft '71 and is connected to the shaft 70merely by shifting collar 162 to the left by means of a shifter fork 164which is operated by a rod 166. The collar 162 is formed with internalsplines which mesh with the external splines 163 on the shaft 166 andwhich, when the collar 162 is moved to the left, also mesh with theexternal splines 170 on the shaft 76 thereby effecting a drivingconnection between the shafts 76 and 1611.

While most of the piping has been omitted from the drawings forsimplification, it will be appreciated by those skilled in the art thata pump or other source of pressurized fluid is provided which suppliesfluid for the operation and cooling of all the clutches and also for thepressure lubrication of all bearings as described hereinafter. Suchpressurized fluid is regulated as to pressure and is controlled bysuitable control valves (not shown) in a manner such that it is admittedselectively to the clutches which are to be actuated. In FIGURE 5, thereappears a fragmentary portion of a conduit or pipe 172 that suppliespressurized fluid to a chamber 174 from which fluid flows throughpassageway 135 and then into the clutch actuating chamber in the mannerpreviously described. A conduit or pipe 176 supplies cooling fluid tothe clutch 611 through the rear housing wall 16 into a chamber 178 andthen through the passageway 151 and the space 152 in the mannerpreviously described to cool the clutch disks. It will be appreciatedthat the clutches 64, 78, 80, 82 and 34 are actuated and cooled in thesame manner described for clutch 61 Each of the bearing assembliesassociated with the clutches is continuously lubricated by fluid underpressure and this is illustrated in FIGURE 5. For example, a passageway179 directs pressurized fluid from passageway 151 through bearing 2%continuously. Each of the other bearing assemblies in the transmissionalso is continuously lubricated in a similar manner and this isillustrated by the conduit 1811, a fragment of which is illustrated inFIGURE 4. The conduit 1811 directs pressurized fluid through an opening132 and provides for the continuous flow of lubricant through thebearing assembly 106.

As shown in FIGURES 1 and 4, a cover member 184 is secured to the fronthousing wall 14 for enclosing the two clutches '78 and 82 and the threegears 72, 9t} and 92. A similar cover member 186 is secured to the rearhousing wall 16 for enclosing the four clutches 60, 64, 80 and 84 andthe five gears 62, 66, 68, 86 and 88. The cover member 186 also servesto support a bearing assembly 187 in which the power take-off shaft 161}is rotatably mounted. The bottom housing wall 20 is provided with anopening 188 which is enclosed by a pan or sump member 190 having a drainplug 192. The pan 191D provides a reservoir for the liquid used in thetransmission for lubrication, cooling and actuation of the clutches. Thetransmission may be installed within a vehicle or the like by the use ofbolts or other securing devices disposed through the openings 194 in thebosses 196 of the housing 12.

The transmission described and illustrated herein provides for therotation of the output shaft 98 in one direction at any one of eightdifferent gear ratios and in the other direction at any one of fourdifferent gear ratios.

This transmission is intended primarily for use in a vehicle; thereforethe two directions will be referred to in the following description ofthe operation of the transmission as forward and reverse. Alsohereinafter, the clutch 60 is referred to as a first forward-driveclutch, the clutch 34 as a second forward-drive clutch and the clutch 64as a reverse-drive clutch. To operate the output shaft 98 in any one ofa first set of four ratios in a forward direction, the firstforward-drive clutch 60 is engaged. The first forward ratio is providedby engaging clutch 7 8 in addition to clutch 60. The drive can then betraced from input shaft 26 through clutch 60 and gears 62 and 68 toidler shaft 70 and then through gears 72 and 90 and through clutch '78to intermediate shaft 74 from which gears 94 and 96 drive output shaft98. A second forward ratio may be obtained by disengaging the clutch 78and engaging the clutch 82. In this ratio the drive is the same down tothe idler shaft 7 8 from which it may be traced through gears '72 and92, through clutch 82 to intermeditae shaft '76, and then through gears180 and 102 to the output shaft 98. If a third forward ratio is desired,clutch 82 is disengaged and clutch 80 is engaged. The drive may then betraced from the gear 68 through the gear 86 and the clutch 80 to theshaft 74 and then through gears 94 and 96 to the shaft 98. A fourthforward ratio is provided by disengaging clutch 88 and engaging clutch84 whereupon the drive is from the gear 68 through the gear 88 to theclutch 8 and then through the shaft 76 and the gears I08 and 182 to theshaft 98.

When the first forward-drive clutch 60 is disengaged and the secondforwarddrive clutch 34 is engaged, the output shaft 98 may be operatedin any one of a second set of four ratios in a forward direction. Inthis case, the drive may be traced from the input shaft 26 through theclutch 34 and the gears 37 and 73 to the idler shaft '70 which willrotate in the same direction as, but at a higher speed than, when clutch68 is engaged. Each one of the four different drive ratios may then beestablished between the idler gear 68 or the idler shaft '70 and theoutput shaft 98 by selectively engaging the ratio clutches 78, 82, 88and 84. The four several paths of power transmission between the idlergear 68 or the idler shaft 70 and the output shaft 98 are the same asdescribed above in connection with the first set of four ratios in aforward direction. In sum, engagement of the first forward-drive clutchat} conditions the transmission for four forward drive ratios, whileengagement of the second forward-drive clutch 34 conditions thetransmission for four additional forward drive ratios.

When a change in drive ratios is made among the ratio clutches 78, 8t 82and 84, it will be appreciated that the drum of the clutch that isengaged is already operating at the desired speed. Consider, forexample, the ratio change mentioned hereinbefore in which clutch '78 isdisengaged and the clutch 82 is engaged. The gear 92 on the drum of theclutch 82 is in constant mesh with the gear 72 the same as the gear 98on the clutch drum 78.

'The drum of the clutch 82 therefore rotates continuously during thetime that the clutch 78 is applied. Assuming that the engine speedremains constant during a shift, then the-clutch drum 82 will beoperating at the same speed after the shift as before, although it willbe understood that if such a shift is made under load, that is, withouttemporarily removing the load connected to the output shaft, there willbe a momentary reduction in the speed of the drum of the clutch 82during engagement of this clutch as the shaft 76, gears I and 102 on theoutput shaft and the load connected thereto are accelerated to speedscorresponding to the speed of the drum or the clutch 82. The operationof this transmission is similar in this respect for all ratio changesinvolving the ratio clutches 78, 82, 8t) and 84- whether shifting up orshifting down.

To operate the output shaft 98 in any one of four ratios in a reversedirection, the second forward-drive clutch 34 is disengaged and thereverse-drive clutch 64 is engaged. Reverse drive may be traced from theinput shaft 26 through the clutch drum 40 and the gears 42 and 30 to thereverse shaft 28, and then through clutch 64 and gears 66 and 68 to theidler shaft 70 which then rotates in the opposite direction to thatpreviously described when either of the forward-drive clutches or 34were engaged. It will be understood that each of the first four ratiospreviously described for forward operation when the clutch 69 wasengaged may be obtained for reverse operation and may be traced in thesame manner from the idler gear 68 or the idler shaft 70. The onlydifference is that the idler shaft 70 now is turning in the oppositedirection so that the output shaft likewise turns in the oppositedirection. As illustrated, the gears 42 and 30 are identical as are thegears 62 and 66. Therefore, engagement of the first forward-drive clutch60 conditions the transmission for four forward drive ratios, whileengagement of the reverse-drive clutch 64 conditions the transmissionfor four reverse drive ratios, the several ratios of the multiple gearreduction paths between the input and output shafts 26 and 98 beingexactly the same for both directions of rotation.

Referring now to FIGURE 7, there is shown at the left a developedschematic diagram of the transmission 10 with all shaft centers lying ina single plane. Each of the shafts and gears and clutches is numbered tocorrespond with the preceding figures and it is indicated by the dashedline 280 that gear 66 is in mesh with gear 68. In a similar manner it isindicated by dashed line 202 that gear 88 is in mesh with gear 68 and bydashed line 284 that gear 92 is in mesh With gear 72. At the right ofFIGURE 7 is shown a diagram of the actual location of the centers of thevarious shafts (viewed from the rear) and each of these is connected bya dashed line to the respective shafts in the left portion of FIGURE 7.

From the foregoing description, it will be appreciated that the numberof different parts that must be manufactured for the transmission 18 aremaintained at a minimum. Clutch assemblies 60, 64, and 84 are allidentical and clutch assemblies '78 and 82 are identical to each other.Moreover, the shafts 74 and 76 are identical, and the gear 94- isidentical to the gear 102, while the gear 96 is identical to the gear108. Thus, with respect to the two intermediate shaft assemblies, it ispossible to manufacture two complete sets of parts which are identicalinstead of manufacturing two completely dissimilar sets of parts. Toachieve the desired gear ratios two of the final drive gears, that isgears and 182 are reversed during assembly so that the gear 102 with thesmaller number of teeth is on the output shaft 98.

In addition, it is possible to utilize parts from the transmissiondescribed and illustrated herein in other transmissions of the samedesign but of different sizes. Thus, for transmissions having lowercapacity requirements, clutches identical to clutches 6t), 64, 8t) and84 may be used in place of the clutches 78 and 82, while for atransmission having higher capacity requirements clutches identical toclutches 78 and 82 may be used in place of the clutches 60, 64, 80 and84. Moreover, it is possible readily to adjust gear ratios withoutchanging the basic construction of the transmission. For example, it ispossible to change the number of teeth on the gears 94 and 96 withoutchanging any other parts of the transmission and thereby achieve achange in the gear reductions of the first and third ratios of each setof ratios. The gears 100 and 102 may be similarly changed, as may alsoother gear combinations such as 72, 9t) and 92, or 68, 86 and 88, or 37and 73.

For further details concerning the various advantages and otherembodiments of transmissions upon which the transmission hereindisclosed in an improvement, reference may be had to the aforesaidco-pending application of Ronald H. Bolster.

While I have shown and described what I believe to be a preferredembodiment of my present invention, it will be understood by thoseskilled in the art that various rearrangements and modifications may bemade therein without departing from the spirit and scope of myinvention.

I claim:

1. In a transmission, an input shaft, 21 first clutch gear rotatable onsaid input shaft, a first forward-drive clutch adapted to selectivelyconnect said first clutch gear to said input shaft, a reverse shaft, asecond clutch gear rotatable on said reverse shaft, a reverse-driveclutch adapted to selectively connect said second clutch gear to saidreverse shaft, a second forward-drive clutch including a hub memberrotatably mounted on said input shaft, a plurality of friction diskmembers carried by said hub member for rotation therewith, a drum memberhaving a radial flange portion secured to said input shaft and agenerally axial cylindrical portion carrying a plurality of frictiondisk members interleaved with said friction disk members on said hubmember, and means for compressing together said disk members of said huband drum members for clutching said hub member to said input shaft, saidcylindrical portion of said drum member having a first drive gear, saidhub member having a second drive gear, a gear secured to said reverseshaft and in constant mesh with said first drive gear, and gear meansselectively driven from said first and second clutch gears and saidsecond drive gear.

2. A transmission comprising a plurality of rotatable shafts arranged inparallel relation including an input shaft, a reverse shaft, an outputshaft and a pair of intermediate shafts, clutch means associated withsaid input shaft and including a hub member rotatably mounted on saidinput shaft, a plurality of friction disk members carried by said hubmember for rotation there with, a drum member secured to said inputshaft and carrying a plurality of friction disk members interleaved withsaid friction disk members on said hub member, and means for compressingtogether said disk members of said hub and drum members for clutchingsaid hub member to said input shaft, said drum member having a firstdrive gear, said hub member having a second drive gear, a gear securedto said reverse shaft and in constant mesh with said first drive gear,means for driving said intermediate shafts selectively from said inputor reverse shafts or said second drive gear including a plurality ofgears and four clutches associated with said intermediate shafts, andgear means for drivingly interconnecting said intermediate shafts andsaid output shaft.

3. A transmission comprising a plurality of rotatable shafts arranged inparallel relation including an input shaft, a reverse shaft, an outputshaft and a pair of intermediate shafts, clutch means associated withsaid input shaft and including a hub member rotatably mounted on saidinput shaft, a plurality of friction disk members carried by said hubmember for rotation therewith, a drum member secured to said input shaftand carrying a plurality of friction disk members interleaved with saidfriction disk members on said hub member, and means for compressingtogether said disk members of said hub and drum members for clutchingsaid hub member to said input shaft, said drum member having a firstdrive gear, said hub member having a second drive gear, a gear securedto said reverse shaft and in constant mesh with said first drive gear,means for driving said intermediate shaft selectively from said input orreverse shafts or said second drive gear including a plurality of gearsand four clutches associated with said intermediate shafts, first andsecond output gears secured to said output shaft for the rotationthereof, a gear secured to one of said intermediate shafts and inconstant mesh with said first output gear, and

a gear secured to the other of said intermediate shafts and in constantmesh with said second output gear.

4. In a transmission, an input shaft, a first clutch gear rotatable onsaid input shaft, a first forward-drive clutch adapted to selectivelyconnect said first clutch gear to said input shaft, a reverse shaft, asecond clutch gear rotatable on said reverse shaft, a reverse-driveclutch adapted to selectively connect said second clutch gear to saidreverse shaft, a second forward-drive clutch associated with said inputshaft intermediate of the ends thereof and including a hub memberrotatably mounted on said input shaft, a plurality of friction diskmembers carried by said hub member for rotation therewith, a drum membersecured to said input shaft and carrying a plurality of friction diskmembers interleaved with said friction disk members on said hub member,and means for compressing together said disk members of said hub anddrum members for clutching said hub member to said input shaft, saiddrum member having a first drive gear, said hub member having a seconddrive gear, a gear secured to said reverse shaft and in constant meshwith said first drive gear, a pair of intermediate shafts, fouradditional ratio clutch gears positioned respectively on the ends ofsaid pair of intermediate shafts, four ratio clutches adapted toselectively connect: said four additional clutch gears to the respectiveends of said intermediate shafts, an idler shaft, a first idler gearsecured to said idler shaft and in constant mesh with said first andsecond clutch gears and also in constant mesh with two of said ratioclutch gears, a second idler gear secured to said idler shaft and inconstant mesh with the other two of said ratio clutch gears, a thirdidler gear secured to said idler shaft and in constant mesh with saidsecond drive gear, a first gear secured to one of said intermediateshafts, a second gear secured to the other of said intermediate shafts,an output shaft, and a pair of gears secured to said output shaft and inconstant mesh respectively with said first and second gears on saidintermediate shafts.

5. A multi-ratio change speed transmission providing eight drive ratiosin one direction and four drive ratios in the other direction comprisingsix rotatable shafts arranged in parallel relation including an inputshaft, a reverse shaft, an idler shaft, a pair of intermediate shaftsand an output shaft, 21 first forward-drive clutch located at one end ofsaid input shaft, a reverse-drive clutch located at one end of saidreverse shaft, four ratio clutches located respectively at the ends ofsaid pair of intermediate shafts, each of said six clutches including aplurality of friction disk members carried by the respective shaft endfor rotation therewith, a rotatable drum surrounding the respectiveshaft end and carrying a plurality of friction disk members interleavedwith said friction disk members on the shaft, and means for compressingthe disk assembly of each clutch for clutching the drum to itsrespective shaft end, each of said clutch drums having a drum gearconnected thereto for rotation therewith, a second forward-drive clutchassociated with said input shaft intermediate of the ends thereof andincluding a hub member rotatably mounted on said inputshaft, a pluralityof friction disk members carried by said hub member for rotationtherewith, a drum member secured to said input shaft and carrying aplurality of friction disk members interleaved with said friction diskmembers on said hub member, and means for compressing together said diskmembers of said hub and drum members for clutching said hub member tosaid input shaft, said drum member secured to said input shaft having afirst drive gear, said hub member having a second drive gear, a gearsecured to said reverse shaft and in constant mesh with said first drivegear, a first idler gear secured to said idler shaft and in constantmesh with said drum gears associated with said input shaft and saidreverse shaft and also in constant mesh with the drum gears of two ofsaid ratio clutches, a second idler gear secured to said idler shaft andin constant mesh with the drum gears of the other two of said ratioclutches, a third idler gear secured to said idler shaft and in constantmesh with said second drive gear, a first gear secured to one of saidintermediate shafts, a second gear secured to the other of saidintermediate shafts, and a pair of gears secured to said output shaftand in constant mesh respectively with said first and second gears onsaid intermediate shaft.

6. A multi-ratio change speed transmission providing eight drive ratiosin one direction and four drive ratios in the other direction comprisinga housing having front and rear vertically disposed walls forming aspace therebetween, six rotatable shafts journaled in said housing andarranged in parallel relation including an input shaft, a reverse shaft,an idler shaft, a pair of intermediate shafts and an output shaft, afirst forward-drive clutch located at one end of said input shaftoutwardly of said rear wall, a reverse-drive clutch located at one endof said reverse shaft outwardly of said rear wall, four ratio clutcheslocated respectively at the ends of said pair of intermediate shaftsoutwardly of said front and rear walls respectively, each of said siXclutches including a plurality of friction disk members mounted on therespective shaft end for rotation therewith, a rotatable drumsurrounding the respective shaft end and carrying a plurality offriction disk members interleaved with said friction disk members on theshaft, and means for compressing the disk assembly of each clutch forclutching the drum to its respective shaft end, each of said clutchdrums having a drum gear connected thereto for rotation therewith, asecond forward-drive clutch associated with said input shaftintermediate of said front and rear walls and including a hub memberrotatably mounted on said input shaft, a plurality of friction diskmembers carried by said hub member for rotation therewith, a drum membersecured to said input shaft and carrying a plurality of friction diskmembers interleaved with said friction disk members on said hub member,and means for compressing together said disk members of said hub anddrum members for clutching said hub member to said input shaft, saiddrum member secured to said input shaft having a first drive gear, saidhub member having a second drive gear, a gear secured to said reverseshaft and in constant mesh with said first drive gear, a first idlergear secured to said idler shaft outwardly of said rear wall and inconstant mesh with said drum gears associated with said input shaft andsaid reverse shaft and also in constant mesh with the drum gears of twoof said ratio clutches, a second idler gear secured to said idler shaftoutwardly of said front wall and in constant mesh with the drum gears ofthe other two of said ratio clutches, a third idler gear secured to saididler shaft and in constant mesh with said second drive gear, a firstgear secured to one of said intermediate shafts intermediate of saidfront and rear walls, a second gear secured to the other of saidintermediate shafts intermediate of said front and rear walls, and apair of gears secured to said output shaft intermediate of said frontand rear walls and in constant mesh respectively with said first andsecond gears on said intermediate shaft.

7. The multi-ratio change speed transmission of claim 6 wherein saidinput shaft is located near the top of said housing walls, said reverseshaft is positioned laterally of said input shaft, said idler shaft islocated at a level below said input and reverse shafts, saidintermediate shafts are located at a level below said idler shaft, andsaid output shaft is located at a level below said intermediate shafts.

References Cited by the Examiner UNITED STATES PATENTS 3,126,752 3/1964Bolster 74359 3,181,385 5/1965 Siler 74-360 DAVID J. WILLIAMOWSKY,Primary Examiner.

H. S. LAYTON, Assistant Examiner.

1. IN A TRANSMISSION, AN INPUT SHAFT, A FIRST CLUTCH GEAR ROTATABLE ONSAID INPUT SHAFT, A FIRST FORWARD-DRIVE CLUTCH ADAPTED TO SELECTIVELYCONNECT SAID FIRST CLUTCH GEAR TO SAID INPUT SHAFT, A REVERSE SHAFT, ASECOND CLUTCH GEAR ROTATABLE ON SAID REVERSE SHAFT, A REVERSE-DRIVECLUTCH ADAPTED TO SELECTIVELY CONNECT WITH SECOND CLUTCH GEAR TO SAIDREVERSE SHAFT, A SECOND FORWARD-DRIVE CLUTCH INCLUDING A HUB MEMBERROTATABLY MOUNTED ON SAID INPUT SHAFT, A PLURALITY OF FRICTION DISKMEMBERS CARRIED BY SAID HUB MEMBER FOR ROTATION THEREWITH, A DRU, MEMBERHAVING A RADIAL FLANGE PORTION SECURED TO SAID INPUT SHAFT AND AGENERALLY AXIAL CYLINDRICAL PORTION CARRYING A PLURALITY OF FRICTIONDISK MEMBERS INTERLEAVED WITH SAID